diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2024-03-18 14:41:10 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-04-23 17:35:25 +0200 |
| commit | 5c3131c392f84c660033d511ec39872d8beb4b1e (patch) | |
| tree | 90bee47c8da028b46a87c8f4d975b06397499a32 | |
| parent | 08b2d15cdd0d3fbbe37ce23bf192b770db3a7539 (diff) | |
KVM: track whether guest state is encrypted
So far, KVM has allowed KVM_GET/SET_* ioctls to execute even if the
guest state is encrypted, in which case they do nothing. For the new
API using VM types, instead, the ioctls will fail which is a safer and
more robust approach.
The new API will be the only one available for SEV-SNP and TDX, but it
is also usable for SEV and SEV-ES. In preparation for that, require
architecture-specific KVM code to communicate the point at which guest
state is protected (which must be after kvm_cpu_synchronize_post_init(),
though that might change in the future in order to suppor migration).
From that point, skip reading registers so that cpu->vcpu_dirty is
never true: if it ever becomes true, kvm_arch_put_registers() will
fail miserably.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | accel/kvm/kvm-all.c | 17 | ||||
| -rw-r--r-- | include/sysemu/kvm.h | 2 | ||||
| -rw-r--r-- | include/sysemu/kvm_int.h | 1 | ||||
| -rw-r--r-- | target/i386/sev.c | 1 |
4 files changed, 18 insertions, 3 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index d58916e33a..d6ebadbf38 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2703,7 +2703,7 @@ bool kvm_cpu_check_are_resettable(void) static void do_kvm_cpu_synchronize_state(CPUState *cpu, run_on_cpu_data arg) { - if (!cpu->vcpu_dirty) { + if (!cpu->vcpu_dirty && !kvm_state->guest_state_protected) { int ret = kvm_arch_get_registers(cpu); if (ret) { error_report("Failed to get registers: %s", strerror(-ret)); @@ -2717,7 +2717,7 @@ static void do_kvm_cpu_synchronize_state(CPUState *cpu, run_on_cpu_data arg) void kvm_cpu_synchronize_state(CPUState *cpu) { - if (!cpu->vcpu_dirty) { + if (!cpu->vcpu_dirty && !kvm_state->guest_state_protected) { run_on_cpu(cpu, do_kvm_cpu_synchronize_state, RUN_ON_CPU_NULL); } } @@ -2752,7 +2752,13 @@ static void do_kvm_cpu_synchronize_post_init(CPUState *cpu, run_on_cpu_data arg) void kvm_cpu_synchronize_post_init(CPUState *cpu) { - run_on_cpu(cpu, do_kvm_cpu_synchronize_post_init, RUN_ON_CPU_NULL); + if (!kvm_state->guest_state_protected) { + /* + * This runs before the machine_init_done notifiers, and is the last + * opportunity to synchronize the state of confidential guests. + */ + run_on_cpu(cpu, do_kvm_cpu_synchronize_post_init, RUN_ON_CPU_NULL); + } } static void do_kvm_cpu_synchronize_pre_loadvm(CPUState *cpu, run_on_cpu_data arg) @@ -4099,3 +4105,8 @@ void query_stats_schemas_cb(StatsSchemaList **result, Error **errp) query_stats_schema_vcpu(first_cpu, &stats_args); } } + +void kvm_mark_guest_state_protected(void) +{ + kvm_state->guest_state_protected = true; +} diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index 2cba899270..14b1ddb3be 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -539,6 +539,8 @@ bool kvm_dirty_ring_enabled(void); uint32_t kvm_dirty_ring_size(void); +void kvm_mark_guest_state_protected(void); + /** * kvm_hwpoisoned_mem - indicate if there is any hwpoisoned page * reported for the VM. diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h index 94488d2c1a..227b61fec3 100644 --- a/include/sysemu/kvm_int.h +++ b/include/sysemu/kvm_int.h @@ -87,6 +87,7 @@ struct KVMState bool kernel_irqchip_required; OnOffAuto kernel_irqchip_split; bool sync_mmu; + bool guest_state_protected; uint64_t manual_dirty_log_protect; /* The man page (and posix) say ioctl numbers are signed int, but * they're not. Linux, glibc and *BSD all treat ioctl numbers as diff --git a/target/i386/sev.c b/target/i386/sev.c index b8f79d34d1..c49a8fd55e 100644 --- a/target/i386/sev.c +++ b/target/i386/sev.c @@ -755,6 +755,7 @@ sev_launch_get_measure(Notifier *notifier, void *unused) if (ret) { exit(1); } + kvm_mark_guest_state_protected(); } /* query the measurement blob length */ |